Magnetic-sensitization biosensor based on multi-field coupling for MMP-3 detection

Matrix metalloproteinase 3(MMP-3) has attracted increasing attention as a biomarker for osteoarthritis (OA) due to its crucial role in the early prevention and diagnosis of the disease. In this study, we achieved magnetic electric coupling and magnetic sensitization by doping magnetic nanoparticles into the conversion layer of the surface stress sensor to introduce magnetic force. Under a magnetic field, the magnetic effect of polydimethylsiloxane composite film doped with Fe 3 O 4 nanoparticles eliminates the gravity interference of sensitive film and magnifies its surface stress-induced concave convex deformation. The detection of OA-related MMP-3 is used as a proof-of-concept of the magnetic sensitization of the biosensor, which achieved a limit of detection (LOD) of 3.16 ng/mL, a significantly lower value than without a magnetic field. Moreover, the magneto-stress-electric coupled biosensor exhibited high specificity, selectivity, and stability. Overall,the results demonstrate that magnetic sensitization improves the performance of surface stress biosensors in detecting MMP-3. The biosensor also provides a platform for sensitive qualitative and quantitative clinical detection of OA markers.